Project Summary/ Abstract Social anxiety disorder (SAD) and eating disorders (EDs) are common and debilitating disorders that are highly comorbid[7-14]. Conceptualizations of comorbidity suggest that there may be underlying genetic and environmental vulnerabilities that create risk for multiple disorders[1-4]. Research on the shared vulnerabilities of SAD and EDs suggest that fear of negative evaluation may be a common underlying risk factor[29-31]. However, relatively little is known about the development of fear of negative evaluation into SAD and EDs and the underlying genetic vulnerabilities common to both disorders. Thus, the aims of this proposal are to examine the shared environmental and genetic vulnerabilities of these disorders and to develop a new model in which fear of negative evaluation and fear of negative evaluation of ones appearance, or social appearance anxiety, contribute to both SAD and EDs. The current project proposes three studies to address these aims. In Study 1 we will test for shared genetic risk between SAD and EDs using an archival data set of twin pairs. In Study 2 the contribution of fear of negative evaluation and social appearance anxiety on social anxiety and disordered eating will be tested longitudinally over six months using measures of social anxiety and disordered eating with strong psychometric properties. In Study 3 fear of negative evaluation and social appearance anxiety will be experimentally primed using a modified speech task. Eating behaviors, state social anxiety, and galvanic skin response will be measured as dependent outcomes. This experiment will test whether an environmental trigger of fear of negative evaluation and social appearance anxiety cause eating and social anxiety outcomes. The integration of these studies will provide the skills for future research that tests a model of vulnerability spanning from genes to self-report of traits and behavior. Results from these studies and from future potential research may lead to the creation of treatments that address genetic and environmental vulnerabilities of both SAD and EDs in the same treatment protocol.